Automotive Service Excellence (ASE) A6 Electrical/Electronic SystemsBattery Diagnosis and ServiceEasy
A technician is performing battery maintenance on a conventional flooded lead-acid battery. They notice that the electrolyte level in one cell is significantly lower than the others. Which of the following is the most appropriate action?
- AReplace the battery immediately.
- BPerform a specific gravity test on all cells.
- CAdd distilled water to the low cell.
- DAdd battery acid to the low cell.
Show answer & explanationAnswer & explanation
Correct answer: C. Add distilled water to the low cell.
In a conventional flooded lead-acid battery, water evaporates over time, leading to lower electrolyte levels. Only distilled water should be added to replenish the level, as adding acid would alter the electrolyte's specific gravity beyond optimal levels.
Why the other options are wrong
- A. Replacing the battery might be premature if only water is needed.
- B. A specific gravity test would be useful after adding water, but the immediate action is to replenish the lost water.
- D. Adding battery acid would increase the specific gravity and damage the cell.
Flooded Lead-Acid Battery Electrolyte Maintenance
Regularly checking and topping off electrolyte levels in conventional flooded lead-acid batteries using only distilled water.
- Water evaporates during charging and normal operation.
- Only distilled water should be added.
- Low electrolyte exposes plates, reducing capacity and lifespan.
Memory trick: When the battery 'drinks' and gets low, only give it 'pure water' to quench its thirst.